The present invention relates to level sensing apparatus, and more particularly to an electronic level detector for generating a signal or other indication of liquid level height in a process tank.
One prior system for detecting the level of liquid in a tank is shown and described in DeMeyer U.S. Pat. No. 3,245,425. This system includes a displacer which follows changes in liquid level in the tank. A magnetic armature is connected to the displacer to move therewith, within a vertical tube of nonmagnetic material secured to the top of the tank. Movements of the armature are followed by a magnet which is positioned adjacent the exterior of the tube. The magnet is secured to the end of a lever which carries an indicating dial to provide an indication of changes in liquid level. The system also effects process control of conditions within the tank by means of pneumatic control apparatus actuated by the lever.